This study is part of a national undertaking to demonstrate the effectiveness of two well-defined, short-term psychotherapies as compared against an established antidepressant medication. Psychotherapists (Ph.D's and M.D.'s) have receive specialty training in either cognitive/behavior therapy (C/B) at the University of Pennsylvania or interpersonal psychotherapy (ITP) at Yale University, while psychiatrists have received further instruction in administering Imipramine and placebo medications in a double-blind design at the Rush Presbyterian St. Luke's Medical Center in Chicago. Patients are undergoing extensive psychological assessment, as well as medical evaluations. Ss are assigned randomly to the several treatment conditions after meeting the stringent "Research Diagnostic Criteria (RDC) for Major Depressive Disorder (MDD). The major aims of the pilot study (first 3 years) are to test: 1) the effectiveness of the training programs in enhancing experienced clinicians' treatment skills, 2) the differential effectiveness of the various treatments as revealed by the multiple dependent measures, 3) the prophylactic value of the different treatments in respect to relapse rates, and 4) the feasibility of applying stringent diagnostic criteria in the selection of patients.